travis: update go versions

[dvrkps]

No description provided.

[liangchenye]

@dvrkps you need to sign your commit.

[wking]

The Signed-off-by needs to go on all the commits. With fc42d47 you have:

$ git log -2 origin/pr/482
commit fc42d470ed7680af5faeda56d221d2ec9af537ab
Author: Davor Kapsa <dvrkps@users.noreply.github.com>
Date:   Fri Sep 22 21:26:38 2017 +0200

    sign PR
    
    Signed-off-by: Davor Kapsa <davor.kapsa@gmail.com>

commit f47ed5f6751f2e6ccd14afcb29e182a021b5ba61
Author: Davor Kapsa <dvrkps@users.noreply.github.com>
Date:   Thu Sep 21 20:56:29 2017 +0200

    travis: update go versions

Also, PullApprove has had problems in the past with Signed-off-by email addresses that don't match the Author email address.

So I think you want to squash down to a single commit where your author/committer email address matches your Signed-off-by address. If you need some help with the Git, you can probably allow edits from maintainers and one of them can straighten out your branch.

[dvrkps]

I open #487